U.S. Pat. No. 4,955,442 illustrates a steering mechanism for converting the rotational movement of a steering wheel to linear actuation of one or the other of a pair of pressure regulating pilot valves connected to the main steering control. That mechanism includes an input shaft and a single actuating cam which are conjointly rotatable away from a neutral position in either direction. A cam follower assembly is cooperatively associated with a substantially spiral shaped cam slot defined in the actuating cam and includes a cam following roller wheel received in the guide slot. The cam follower assembly also includes a bell crank supporting the roller wheel and indirectly connected to the pilot valves so that rotating the input shaft imparts controlled displacement of the control valves.
The steering mechanism of the above noted patent is overly complex and requires an excessive amount of space. Thus it would be desirable to have a simpler, more compact and more economical steering valve that provides substantially the same operating characteristics as that patent.
The present invention is directed to overcoming one or more of the problems as set forth above.